Glue Dispersion
Which pin (Spiral-Grooved or Multi-Groove) offers the better holding power? There is no definitive answer, as each customer’s application differs from the others. Oftentimes the manufacturer of the customer’s dowel-inserting machinery can give a preference as to which groove would better suit its machinery. Both pins offer excellent glue-dispersion and bonding qualities. As each order is individually manufactured at our plant, we can easily accommodate oversize or undersize (scant) diameter requests.

The Wooden Dowel Pin Advantage

Wooden Dowel Pins increase both the shear and tensile strength of the joint, particularly if the materials being joined are of lower density. Shear strength is the amount of force required for the materials being joined to slide past each other. Tensile strength is the amount of force required to pull the joint apart.

Wooden Dowel Pins handily serve as positioning guides when joining two pieces of wood. In a non-doweled joint, movement will inevitably occur raising the likelihood that the bond will fail.

Wooden Dowel Pins provide a clean finish to the product being joined since the entire pin is not seen once the joint is assembled.

The Proper Method to Measure the Diameter of a Multi-Grooved Pin

The first reading should be taken on the part line groove (Pic A). After turning the pin 1/4, the second reading should be taken at the spot on the dowel perpendicular to the part line groove. (Pic B)

Decisions to make when deciding which type of dowel pin is most suitable for your operation:

Diameter: Ideally, the diameter of the dowel should be approximately 1/3 – and never more than 1/2 – of the thickness of the wood being joined. For example, if your product is 1” thick, you should be considering a dowel pin 3/8” in diameter. If your product is 1-1/4” thick, a 7/16” diameter would be more suitable.

Length: When determining the length of the dowel pin needed remember that 1/16” of space should be left in the boring after pin insertion, to allow for glue disbursement. If you are using a 2” dowel pin, for example, each boring depth should be 1/16” shorter than half the length of the pin, or .9375”

Groove Type: Both Multi- and Spiral-Grooved Dowel pins, when used properly, have ideal bonding strength. Studies have shown that Multi-Grooved Dowel Pin perhaps produces a slightly stronger bond. Additionally, Multi-Grooved Dowel Pins, due to their design, slightly compress upon insertion, which some believe make them easier to work with. Spiral-Grooved Dowel Pins tend to have slightly stricter tolerances. Chicago Dowel encourages customers to obtain samples of both types, and decide which they feel work better in their operation.

Bore Dimensions: The dimensions of the boring should be into which the dowel pin will fit. If you are working with MDF/Particle Board type material, remember that a boring will slightly contract. Borings in solid wood tend to hold their diameter.

Adhesive: A standard PVA wood glue is usually as well as the method of applying it. A standard PVA wood glue is usually sufficient. Be cautious of over gluing as squeeze out might occur. If concerned about this part of the process, please see visit our Pre-Glued Dowel Pin page.

Chicago Dowel Company has been considered the industry gold standard in wooden dowel pin manufacturing since 1950.